The invention relates to a three dimensional matrix, such as porous foam, which has within its porous structure a mechanically-fractured hydrogel that contains a network of fracture channels. More particularly, the gel-in-matrix may contain a mechanically-fractured hydrogel that has been partially dewatered to create the porous network of fracture channels.
Gel-forming materials such as hydrogels are well known for their usefulness in electrophoretic and chromatographic procedures, as well as for the immobilization of biologically active materials. The microporosity of hydrogels allows their use in the electrophoretic separation of macromolecular fragments according to size via their diffusion at different rates through the gel. The permeability of these hydrogels, however, is limited by the small size of the pores in the gel and by the diffusion-controlled flow in such pores. Gel porosity may be enhanced to a limited degree by using low concentrations of the gel forming material, but the resultant gels are ordinarily fragile and difficult to handle.
U.S. Pat. No. 4,452,892 issued to Rosevear concerns the immobilization of biologically active components in a gel-forming material which is retained on or in a support medium like woven cloth or thin section sponge. The support material serves to inhibit sedimentation of the biologically active components prior to and during gelling and to reinforce the gel composite that is formed.
It is evident that the permeability of the gel employed in such gel composites is a controlling factor in the reactivity or activity of the gel composite, when the latter is exposed to a fluid containing species that can interact with the biologically active components immobilized within the gel.
British Patent No. 1,570,485 issued to Winson and European Patent No. 41,934 issued to Laszlo do not concern immobilization of biologically active materials but instead describe foam structures containing polymer particles that are gel-forming and that are capable of imbibing large amounts of water. The foam structure provides a support medium for the gel-forming particles, which only occupy a small fraction of the foam's void volume and which are typically introduced into the foam structure via dry blending with foam pieces or via organic solvent carriers.
These gel composites suffer from drawbacks that limit their utility. The polymer particles may become dislodged from the foam structure unless anchored with a binder material. The difficulty of ensuring uniform distribution of the polymer particles throughout the open cell foam structure places constraints on the maximum usable size of polymer particles and on minimum usable pore size in the foam structure.
The present invention concerns a gel-containing matrix structure that not only possesses the advantages realized by the prior art gel composites but also avoids many of their drawbacks.